Water and hydrocarbons such as oil and gasoline are incompatible phases, thus a number of techniques, such as the use of surface-active agents, have been studied in an effort to decrease the repellency between water and said hydrocarbons. Surface-active agents are expected to be useful for the remediation of shallow, subsurface sites that have been contaminated with hydrocarbons. The introduction of surface-active agents can be used to solubilize or mobilize hydrocarbons adsorbed to soil particles or present as a separate hydrocarbon phase (see, for example, West, C C and Harwell, J H, “Surfactants and Subsurface Remediation” Environ. Sci. Techncl., 1992, 26(12):2324).
Some microbial products can decrease oil-water repellency because they are surface active. Only certain groups of microorganisms are able to produce these surface-active compounds (Neu, T. R (Microbiological Reviews, 1996, 60:151-166). Such biologically produced surface-active compounds have also been suggested for use in remediation of hydrocarbon-contaminated sites. Many biologically produced surface-active compounds are based on production by pure cultures of aerobic microorganisms (for example, U.S. Pat. No. 4,522,261).
There exists a need for an inexpensive and effective method for producing surface-active agents that can be used for improving hydrocarbon-water compatibility, and thus for improving remediation of hydrocarbon-contaminated subsurface sites.